Ich habe dies in meinem BlogRepository

public IQueryable<Subnus.MVC.Data.Model.Post> GetPosts()
    {
        var query = from p in db.Posts
                    let categories = GetCategoriesByPostId(p.PostId)
                    let comments = GetCommentsByPostId(p.PostId)
                    select new Subnus.MVC.Data.Model.Post
                    {
                        Categories = new LazyList<Category>(categories),
                        Comments = new LazyList<Comment>(comments),
                        PostId = p.PostId,
                        Slug = p.Slug,
                        Title = p.Title,
                        CreatedBy = p.CreatedBy,
                        CreatedOn = p.CreatedOn,
                        Body = p.Body
                    };
        return query;
    }

un

public IQueryable<Subnus.MVC.Data.Model.Comment> GetCommentsByPostId(int postId)
    {
        var query = from c in db.Comments
                    where c.PostId == postId
                    select new Subnus.MVC.Data.Model.Comment
                    {
                        Body = c.Body,
                        EMail = c.EMail,
                        Date = c.CreatedOn,
                        WebSite = c.Website,
                        Name = c.Name
                    };

        return query;
    }

private IQueryable<Subnus.MVC.Data.Model.Category> GetCategoriesByPostId(int postId)
    {
        var query = from c in db.Categories
                    join pcm in db.Post_Category_Maps on c.CategoryId equals pcm.CategoryId
                    where pcm.PostId == postId
                    select new Subnus.MVC.Data.Model.Category
                    {
                        CategoryId = c.CategoryId,
                        Name = c.Name
                    };
        return query;
    }

und wenn ich diesen Filter verwende

namespace Subnus.MVC.Data
{
 public static class BlogFilters
 {
    public static IQueryable<Post> WherePublicIs(this IQueryable<Post> qry,bool state)
    {

        return from p in qry
               where p.IsPublic == state
               select p;
    }
 }

}

all das ist im selben Namespace, wenn dieser Hilfe-Namespace Subnus.MVC.Data

wenn ich versuche, dies zu tun

public class BlogService : IBlogService
{
...
    public IList<Post> GetPublicPosts()
    {
         return repository.GetPosts().WherePublicIs(true).ToList();
    }
 ...
 }

das ist im Namespace Subnus.MVC.Service es wirft den Fehler

Method 'System.Linq.IQueryable`1[Subnus.MVC.Data.Model.Comment] GetCommentsByPostId(Int32)' has no supported translation to SQL.